U.S. patent application number 17/036999 was filed with the patent office on 2021-04-01 for gas turbine combustor and its operating method.
The applicant listed for this patent is Mitsubishi Power, Ltd.. Invention is credited to Yasuhiro AKIYAMA, Tomohiro ASAI, Akinori HAYASHI, Yoshitaka HIRATA, Yoshinori MATSUBARA, Shohei YOSHIDA.
Application Number | 20210095599 17/036999 |
Document ID | / |
Family ID | 1000005130817 |
Filed Date | 2021-04-01 |
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United States Patent
Application |
20210095599 |
Kind Code |
A1 |
ASAI; Tomohiro ; et
al. |
April 1, 2021 |
Gas Turbine Combustor and its Operating Method
Abstract
A hydrogen content fuel can be stably ignited using a gaseous
fuel that does not contain hydrogen and dispersibility of the
hydrogen content fuel is enhanced. A gas turbine combustor
including a burner including: a startup fuel pipe in which a
startup fuel circulates; a first main fuel pipe in which a main
fuel circulates, a second main fuel pipe in which the main fuel
circulates; a fuel mixer to which the startup fuel pipe and the
first main fuel pipe are connected; an inner fuel nozzle to which
the fuel mixer is connected; a plurality of outer fuel nozzles to
which the second main fuel pipe is connected; a startup fuel
control valve provided in the startup fuel pipe; a first fuel
control valve provided in the first main fuel pipe; and a second
fuel control valve provided in the second main fuel pipe.
Inventors: |
ASAI; Tomohiro; (Tokyo,
JP) ; YOSHIDA; Shohei; (Yokohama, JP) ;
HIRATA; Yoshitaka; (Yokohama, JP) ; HAYASHI;
Akinori; (Yokohama, JP) ; AKIYAMA; Yasuhiro;
(Yokohama, JP) ; MATSUBARA; Yoshinori; (Yokohama,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Power, Ltd. |
Yokohama-shi |
|
JP |
|
|
Family ID: |
1000005130817 |
Appl. No.: |
17/036999 |
Filed: |
September 29, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F23N 1/002 20130101;
F05D 2240/35 20130101; F23N 2241/20 20200101; F02C 9/40 20130101;
F02C 7/228 20130101; F05D 2270/082 20130101; F23N 2237/02 20200101;
F02C 9/263 20130101; F23R 3/36 20130101; F23D 2900/00014
20130101 |
International
Class: |
F02C 7/228 20060101
F02C007/228; F02C 9/26 20060101 F02C009/26; F02C 9/40 20060101
F02C009/40; F23R 3/36 20060101 F23R003/36; F23N 1/00 20060101
F23N001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 1, 2019 |
JP |
2019-181129 |
Claims
1. A gas turbine combustor comprising a burner including: a startup
fuel pipe in which a startup fuel circulates; a first main fuel
pipe in which a main fuel circulates; a second main fuel pipe in
which the main fuel circulates; a fuel mixer to which the startup
fuel pipe and the first main fuel pipe are connected; an inner fuel
nozzle to which the fuel mixer is connected; a plurality of outer
fuel nozzles to which the second main fuel pipe is connected; a
startup fuel control valve provided in the startup fuel pipe; a
first fuel control valve provided in the first main fuel pipe; and
a second fuel control valve provided in the second main fuel
pipe.
2. The gas turbine combustor according to claim 1, further
comprising: a controller configured to control the startup fuel
control valve, the first fuel control valve, and the second fuel
control valve, wherein the controller executes procedures including
(1) raising an opening degree of the startup fuel control valve to
supply the startup fuel to the inner fuel nozzle, (2) raising an
opening degree of the second fuel control valve to supply the main
fuel to the plurality of outer fuel nozzles when a gas turbine load
rises up to a first set value, and (3) raising an opening degree of
the first fuel control valve to supply a mixed gaseous fuel of the
startup fuel and the main fuel to the inner fuel nozzle when the
gas turbine load further rises up to a second set value.
3. The gas turbine combustor according to claim 2, wherein the
controller executes procedures including (4) closing the first fuel
control valve to stop to supply the main fuel to the inner fuel
nozzle, and lowering the opening degree of the second fuel control
valve when the opening degree of the second fuel control valve is
lowered and the gas turbine load falls down to a third set value,
and (5) closing the second fuel control valve to transition to a
state of single firing of the startup fuel, and subsequently
lowering the opening degree of the startup fuel control valve down
to zero to extinguish the startup fuel when the gas turbine load
further falls down to a fourth set value.
4. The gas turbine combustor according to claim 2, wherein the
controller executes procedures including (4) closing the startup
fuel control valve to stop to supply the startup fuel to the inner
fuel nozzle, and transitioning to a state of single firing of the
main fuel, the state of single firing being a state in which only
the main fuel is jetted from all of the plurality of outer fuel
nozzles and the inner fuel nozzle, when the gas turbine load
further rises up to a third set value.
5. The gas turbine combustor according to claim 4, wherein the
controller executes procedures including (5) lowering the opening
degree of the second fuel control valve, (6) raising the opening
degree of the startup fuel control valve to supply the mixed
gaseous fuel of the startup fuel and the main fuel to the inner
fuel nozzle when the gas turbine load falls down to a fourth set
value, (7) closing the first fuel control valve to stop to supply
the main fuel to the inner fuel nozzle, and lowering the opening
degree of the second fuel control valve when the gas turbine load
further falls down to a fifth set value, and (8) closing the second
fuel control valve to transition to a state of single firing of the
startup fuel, and subsequently lowering the opening degree of the
startup fuel control valve down to zero to extinguish the startup
fuel when the gas turbine load further falls down to a sixth set
value.
6. The gas turbine combustor according to claim 1, wherein the
plurality of outer fuel nozzles are divided into a plurality of
nozzle groups, the second main fuel pipe branches off to a
plurality of branch pipes, and the plurality of branch pipes are
each connected to a corresponding nozzle group.
7. The gas turbine combustor according to claim 1, further
comprising: a plurality of the burners.
8. The gas turbine combustor according to claim 1, further
comprising: a cylindrical liner that forms a combustion chamber;
and an air hole plate disposed at an inlet port of the liner and
including a plurality of air holes that guide compressed air to the
combustion chamber, wherein the inner fuel nozzle and the plurality
of outer fuel nozzles have injection ports oriented to the
corresponding air holes, and are disposed opposite to the
combustion chamber across the air hole plate, and the inner fuel
nozzle and the plurality of outer fuel nozzles are disposed
concentrically.
9. The gas turbine combustor according to claim 1, further
comprising: a cylindrical liner that forms a combustion chamber;
and an air hole plate disposed at an inlet port of the liner and
including a plurality of air holes that guide compressed air to the
combustion chamber, wherein injection ports of the inner fuel
nozzle and the outer fuel nozzles are open to inner wall surfaces
of the air holes.
10. The gas turbine combustor according to claim 1, wherein the
startup fuel is either natural gas or petroleum gas, and the main
fuel is a hydrogen content fuel.
11. A gas turbine combustor operating method using the gas turbine
combustor according to claim 1, comprising: raising an opening
degree of the startup fuel control valve to supply the startup fuel
to the inner fuel nozzle; raising an opening degree of the second
fuel control valve to supply the main fuel to the plurality of
outer fuel nozzles when a gas turbine load rises up to a first set
value; and raising an opening degree of the first fuel control
valve to supply a mixed gaseous fuel of the startup fuel and the
main fuel to the inner fuel nozzle when the gas turbine load
further rises up to a second set value.
12. The gas turbine combustor operating method according to claim
11, further comprising: closing the first fuel control valve to
stop to supply the main fuel to the inner fuel nozzle, and lowering
the opening degree of the second fuel control valve when the
opening degree of the second fuel control valve is lowered and the
gas turbine load falls down to a third set value; and closing the
second fuel control valve to transition to a state of single firing
of the startup fuel, and subsequently lowering the opening degree
of the startup fuel control valve down to zero to extinguish the
startup fuel when the gas turbine load further falls down to a
fourth set value.
13. The gas turbine combustor operating method according to claim
11, further comprising: closing the startup fuel control valve to
stop to supply the startup fuel to the inner fuel nozzle, and
transitioning to a state of single firing of the main fuel, the
state of single firing being a state in which only the main fuel is
jetted from all of the plurality of outer fuel nozzles and the
inner fuel nozzle, when the gas turbine load further rises up to a
third set value.
14. The gas turbine combustor operating method according to claim
13, further comprising: lowering the opening degree of the second
fuel control valve; raising the opening degree of the startup fuel
control valve to supply the mixed gaseous fuel of the startup fuel
and the main fuel to the inner fuel nozzle when the gas turbine
load falls down to a fourth set value; closing the first fuel
control valve to stop to supply the main fuel to the inner fuel
nozzle, and lowering the opening degree of the second fuel control
valve when the gas turbine load further falls down to a fifth set
value; and closing the second fuel control valve to transition to a
state of single firing of the startup fuel, and subsequently
lowering the opening degree of the startup fuel control valve down
to zero to extinguish the startup fuel when the gas turbine load
further falls down to a sixth set value.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to a gas turbine combustor and
its operating method.
2. Description of the Related Art
[0002] In recent years, it has been required to make effective use
of byproduct gas such as coke oven gas produced as byproducts in
iron works and off-gas produced as byproducts in oil refineries
from the viewpoint of mitigation of global warming, utilization of
natural resources, and reduction of power generation cost.
Furthermore, attention has been paid to an integrated coal
gasification combined cycle (IGCC) gasifying coal that is plentiful
resources and generating electric power. In the IGCC, measures for
reducing carbon dioxide (CO.sub.2) emissions by a system (carbon
capture and storage (CCS)) that captures and stores carbon in a
gaseous fuel supplied to a gas turbine are under consideration.
Since the gaseous fuel mainly contains hydrogen (H.sub.2), it is
possible to reduce CO.sub.2 emissions and contribute to mitigation
of global warming, compared with natural gas (mainly containing
methane) normally used in gas turbines. Moreover, power generation
by a pure hydrogen fuel is under consideration for realization of a
future hydrogen-based society. If electric power can be generated
using pure hydrogen as a fuel, zero-emission power generation
without CO.sub.2 emissions can be realized. In this way, a hydrogen
content fuel is regarded as being promising from the viewpoint of
the mitigation of global warming, the utilization of natural
resources, and the reduction of power generation cost.
[0003] However, burning hydrogen results in a local increase in a
maximum adiabatic flame temperature of a combustion zone, compared
with a case of burning natural gas; thus, there is a concern of an
increase in emissions of nitrogen oxides (NOx) that is an
environmental pollutant in combustion gas. Furthermore, because of
a higher burning velocity of hydrogen than that of natural gas,
flashback of a flame to a burner section upstream of a combustor
possibly occurs, which arouses a concern of a reduction in
reliability of the combustor. To address the problems, there is
known a lean combustion type combustor intended to reduce NOx
emissions and prevent flashback of a flame by enhancing fuel
dispersibility and preventing local formation of a high-temperature
flame (Patent Document 1: JP-2003-148734-A, etc.) and the like).
The combustor of this type is configured with, for example, an air
hole plate having a plurality of air holes and a plurality of fuel
nozzles, injects a fuel from each fuel nozzle to the corresponding
air hole, and supplies a coaxial jet formed from a fuel stream and
an air flow surrounding this fuel stream to a combustion
chamber.
[0004] In a case of using a hydrogen content fuel as a fuel of a
gas turbine, there is a concern that when ignition fails within the
combustor, an unburned hydrogen content fuel is emitted from the
combustor, stagnates in the turbine, and is burned in the turbine.
To take measures against the problem, there is known an operating
method of supplying a hydrogen content fuel after ignition of a
startup fuel that does not contain hydrogen. As one type of the
operating method, there is known an example of igniting an oil fuel
and changing over the oil fuel to a hydrogen content fuel (Patent
Document 2: JP-2014-105601-A and Patent Document 3:
JP-2018-71354-A). There is also known an example of co-firing for
making use of part of a plurality of main burners with natural gas
and a remainder thereof with a hydrogen content fuel after igniting
a pilot burner disposed at a center with the natural gas (Patent
Document 4: JP-2016-75448-A).
CITATION LIST
Patent Documents
[0005] Patent Document 1: JP-2003-148734-A
[0006] Patent Document 2: JP-2014-105601-A
[0007] Patent Document 3: JP-2018-71354-A
[0008] Patent Document 4: JP-2016-75448-A
[0009] In JP-2014-105601-A, JP-2018-71354-A, and JP-2016-75448-A,
it is impossible to inject the hydrogen content fuel from fuel
nozzles used in injection of a startup fuel. Owing to this, if a
firing operation transitions to an operation of single firing of
the hydrogen content fuel, then it is impossible to supply the fuel
to fuel injection zones of the fuel nozzles for the startup fuel,
and dispersibility of a gaseous fuel deteriorates, resulting in a
disadvantage in terms of NOx emissions reduction.
[0010] An object of the present invention is to provide a gas
turbine combustor and its operating method that can stably ignite a
hydrogen content fuel using a gaseous fuel that does not contain
hydrogen and enhance dispersibility of the hydrogen content
fuel.
SUMMARY OF THE INVENTION
[0011] To attain the object, the present invention provides a gas
turbine combustor including a burner including: a startup fuel pipe
in which a startup fuel circulates; a first main fuel pipe in which
a main fuel circulates, a second main fuel pipe in which the main
fuel circulates; a fuel mixer to which the startup fuel pipe and
the first main fuel pipe are connected; an inner fuel nozzle to
which the fuel mixer is connected; a plurality of outer fuel
nozzles to which the second main fuel pipe is connected; a startup
fuel control valve provided in the startup fuel pipe; a first fuel
control valve provided in the first main fuel pipe; and a second
fuel control valve provided in the second main fuel pipe.
[0012] According to the present invention, it is possible to stably
ignite a hydrogen content fuel using a gaseous fuel that does not
contain hydrogen and enhance dispersibility of the hydrogen content
fuel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic configuration diagram of a gas turbine
plant configured with a gas turbine combustor according to a first
embodiment of the present invention;
[0014] FIG. 2 depicts a burner provided in the gas turbine
combustor according to the first embodiment of the present
invention, the burner being viewed from a combustion chamber;
[0015] FIG. 3 is an explanatory diagram of a gas turbine combustor
operating method (startup time) according to the first embodiment
of the present invention;
[0016] FIG. 4 is an explanatory diagram of a gas turbine combustor
operating method (stop time) according to the first embodiment of
the present invention;
[0017] FIG. 5 is an explanatory diagram of advantages of the
present invention;
[0018] FIG. 6 is a schematic configuration diagram of a gas turbine
plant configured with a gas turbine combustor according to a second
embodiment of the present invention;
[0019] FIG. 7 is a schematic configuration diagram of a gas turbine
plant configured with a gas turbine combustor according to a third
embodiment of the present invention;
[0020] FIG. 8 depicts a burner provided in the gas turbine
combustor according to the third embodiment of the present
invention, the burner being viewed from a combustion chamber;
[0021] FIG. 9 is an explanatory diagram of a gas turbine combustor
operating method (startup time) according to the third embodiment
of the present invention;
[0022] FIG. 10 is an explanatory diagram of a gas turbine combustor
operating method (stop time) according to the third embodiment of
the present invention;
[0023] FIG. 11 is a schematic configuration diagram of a gas
turbine plant configured with a gas turbine combustor according to
a fourth embodiment of the present invention;
[0024] FIG. 12 depicts a burner provided in the gas turbine
combustor according to the fourth embodiment of the present
invention, the burner being viewed from a combustion chamber;
[0025] FIG. 13 is an explanatory diagram of a gas turbine combustor
operating method (startup time) according to the fourth embodiment
of the present invention; and
[0026] FIG. 14 is an explanatory diagram of a gas turbine combustor
operating method (stop time) according to the fourth embodiment of
the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] Embodiments of the present invention will be described
hereinafter with reference to the drawings.
First Embodiment
--Gas Turbine Plant--
[0028] FIG. 1 is a schematic configuration diagram of a gas turbine
plant configured with a gas turbine combustor according to a first
embodiment of the present invention. FIG. 2 depicts a burner
provided in the gas turbine combustor according to the first
embodiment of the present invention, the burner being viewed from a
combustion chamber.
[0029] A gas turbine plant 1 is configured with an air compressor
2, a gas turbine combustor (hereinafter, abbreviated as
"combustor") 3, a turbine 4, and an electric generator 6. The air
compressor 2 draws in and compresses air a1, and supplies
compressed air a2 to the combustor 3. The combustor 3 mixes up and
burns the compressed air a2 and a gaseous fuel (a startup fuel f1
and a main fuel f2) to produce combustion gas g1. The turbine 4 is
driven by the combustion gas g1 generated in the combustor 3, and
the combustion gas g1 driving the turbine 4 is evolved as exhaust
gas g2. The electric generator 6 is driven by rotational power of
the turbine 4 and generates electric power. It is noted that the
turbine 4 is driven by a startup motor 7 only at a time of
beginning of startup.
--Gas Turbine Combustor--
[0030] The combustor 3 is attached to a casing (not depicted) of
the turbine 4, and configured with a liner (combustion liner) 12, a
flow sleeve (outer casing) 10, a burner 8, and a fuel supplying
system 200. The liner 12 is a cylindrical member and forms a
combustion chamber 5 there inside. The flow sleeve 10 is a
cylindrical member having a larger inside diameter than an inside
diameter of the liner 12 and surrounding an outer circumference of
the liner 12 to form a cylindrical air flow passage 9. An end
portion of the flow sleeve 10 on an opposite side (a left side in
FIG. 1) to the turbine 4 is closed by an end cover 13. The
compressed air a2 from the air compressor 2 circulates in the air
flow passage 9 formed on the outer circumference of the liner 12 by
the flow sleeve 10 in a direction away from the turbine 4, and an
outer circumferential surface of the liner 12 is subjected to
convection cooling by the compressed air a2 flowing in the air flow
passage 9. In addition, many holes are formed in a wall surface of
the liner 12, partial compressed air a3 of the compressed air a2
flowing in the air flow passage 9 flows into the combustion chamber
5 through those holes, and the inner circumferential surface of the
liner 12 is subjected to film cooling by the partial compressed air
a3. Furthermore, the compressed air a2 passing through the air flow
passage 9 and arriving at the burner 8 is jetted together with the
gaseous fuel supplied from the fuel supplying system 200 to the
burner 8, and the gaseous fuel jetted together with the compressed
air a2 is burned. In the combustion chamber 5, a mixed gaseous fuel
of the compressed air a2 and the gaseous fuel is burned to produce
the combustion gas g1, and the combustion gas g1 is supplied to the
turbine 4 via a transition piece (not depicted).
[0031] As depicted in FIG. 1, only one burner 8 is disposed at an
inlet port of the liner 12 (opening in the end portion on the
opposite side to the turbine 4), and configured with an air hole
plate 20, fuel nozzles 21 to 23, and a fuel distributor (fuel
header) 24.
[0032] The air hole plate 20 is a circular plate coaxial with the
liner 12 and disposed at the inlet port of the liner 12 (opening in
the end portion on the opposite side to the turbine 4). The air
hole plate 20 is configured with a plurality of air holes 51 to 53
that guide the compressed air a2 to the combustion chamber 5. The
plurality of air holes 51 to 53 configure a plurality of concentric
annular rows around a central axis O of the liner 12. The air holes
belonging to a first (innermost) row are the air holes 51, those
belonging to a second annular row are the air holes 52, and those
belonging to a third (outermost) annular row are the air holes 53.
The air holes 51 configure inner air holes, while the air holes 52
and 53 configure outer air holes. In the present embodiment, the
air holes 51 to 53 have swivel corners and an outlet port of each
air hole is misaligned to one circumferential side with respect to
an inlet port thereof.
[0033] The fuel nozzles 21 to 23 are supported by the fuel
distributor 24 and disposed opposite to the combustion chamber 5
across the air hole plate 20. The fuel nozzles 21 to 23 correspond
to the air holes 51 to 53 in numbers and positions (one fuel nozzle
corresponds to one air hole), and configure, together with the air
holes 51 to 53, the plurality of concentric annular rows around the
central axis O of the liner 12. The fuel nozzles belonging to the
first (innermost) annular row are the fuel nozzles 21, those
belonging to the second annular row are the fuel nozzles 22, and
those belonging to the third (outermost) annular row are the fuel
nozzles 23. The fuel nozzles 21 configure inner fuel nozzles, while
the fuel nozzles 22 and 23 configure outer fuel nozzles. The fuel
nozzles 21 to 23 have injection ports oriented to the inlet ports
of the corresponding air holes, and inject the gaseous fuel toward
the corresponding air holes. By injecting the fuel from many fuel
nozzles toward the corresponding air holes in this way, a coaxial
jet of the fuel and the air in which surroundings of a fuel stream
are covered with an air stream is dispersed in and injected to the
combustion chamber 5 from each air hole.
[0034] It is noted that the numbers of fuel nozzles and air holes
of the outer annular row are larger due to a difference in a
circumference of a circle among the annular rows. In other words,
the numbers of the fuel nozzles 21 and the air holes 51 (each six
in the example of FIG. 2) in the first (innermost) row are smaller
than those of the fuel nozzles 22 and the air holes 52 (each 12 in
the example of FIG. 2) in the second row. The numbers of the fuel
nozzles 22 and the air holes 52 in the second row are smaller than
those of the fuel nozzles 23 and the air holes 53 (each 18 in the
example of FIG. 2) in the third (outermost) row.
[0035] The fuel distributor 24 is a member that distributes and
supplies the fuel to the fuel nozzles 21 to 23 and configured with
a plurality of fuel cavities 25 and 26 contained inside. Each of
the fuel cavities 25 and 26 is a space that plays a role in
distributing and supplying the gaseous fuel to a plurality of fuel
nozzles belonging to the corresponding annular row. The fuel cavity
25 is formed into a columnar shape on the central axis O of the
liner 12, and the fuel cavity 26 is formed into a cylindrical shape
in such a manner as to surround an outer circumference of the fuel
cavity 25. In the present embodiment, the fuel nozzles 21 are
connected to the fuel cavity 25, and the fuel nozzles 22 and 23 are
connected to the fuel cavity 26. When being supplied to the fuel
cavity 25, the gaseous fuel is distributed to the fuel nozzles 21
disposed in the innermost annular row and is then jetted, and the
gaseous fuel that has been jetted from the fuel nozzles 21 is
jetted together with the compressed air a2 from the air holes 51 to
the combustion chamber 5. When being supplied to the fuel cavity
26, the gaseous fuel is distributed to the fuel nozzles 22 and 23
disposed in the second and third annular rows and is then jetted,
and the gaseous fuel that has been jetted from the fuel nozzles 22
and 23 is jetted together with the compressed air a2 from the air
holes 52 and 53 to the combustion chamber 5.
[0036] The fuel supplying system 200 is configured with fuel
supplying sources 55 and 56, a startup fuel pipe 57, a main flow
pipe 58, main fuel pipes 59 and 60, a fuel mixer 61, fuel shut
valves 62 and 63, and fuel control valves 64 to 66.
[0037] The fuel supplying source 55 is a source of supplying the
startup fuel f1. As the startup fuel f1, a fuel that does not
contain hydrogen or a gaseous fuel with a hydrogen content of a few
% (for example, 5%) such as a hydrocarbon fuel is used.
Representative examples of the hydrocarbon fuel include natural gas
mainly containing methane and petroleum gas mainly containing
propane or butane. The fuel supplying source 56 is a source of
supplying the main fuel f2. As the main fuel f2, a hydrogen content
fuel with a hydrogen content of a few % (for example, 5%) to
several tens of % or higher such as byproduct gas is used. Pure
hydrogen (hydrogen content of 100%) is a kind of the hydrogen
content fuel.
[0038] The startup fuel pipe 57 extends from the fuel supplying
source 55 and the startup fuel f1 circulates in the startup fuel
pipe 57. The main flow pipe 58 extending from the fuel supplying
source 56 branches off to the first main fuel pipe 59 and the
second main fuel pipe 60, and the main fuel f2 circulates in these
main fuel pipes 59 and 60. The startup fuel pipe 57 and the first
main fuel pipe 59 are connected to the fuel mixer 61 and merge
together. The fuel mixer 61 is connected to the fuel cavity 25 via
a communication duct 68, and connected to the inner fuel nozzles 21
via the fuel cavity 25. The second main fuel pipe 60 is connected
to the fuel cavity 26, and connected to the outer fuel nozzles 22
and 23 via the fuel cavity 26. The fuel shut valve 62 and the fuel
control valve (startup fuel control valve) 64 are provided in the
startup fuel pipe 57. In addition, the fuel control valve 65 (first
fuel control valve) is provided in the first main fuel pipe 59, and
the fuel control valve 66 (second fuel control valve) is provided
in the second main fuel pipe 60. The fuel shut valve 63 is provided
between a branch portion, in which the main flow pipe 58 branches
off to the main fuel pipes 59 and 60, and the fuel supplying source
56 (that is, provided in the main flow pipe 58).
[0039] Opening the fuel shut valve 62 enables supply of the startup
fuel f1 to the startup fuel pipe 57, and closing the fuel shut
valve 62 causes shut-off of the supply of the startup fuel f1 to
the startup fuel pipe 57. Opening the fuel shut valve 63 enables
supply of the main fuel f2 to the main fuel pipes 59 and 60, and
closing the fuel shut valve 63 causes shut-off of the supply of the
main fuel f2 to the main fuel pipes 59 and 60. The fuel control
valves 64 to 66 each play a role in regulating a flow rate of the
fuel in response to an opening degree, and can shut off a stream of
the fuel by being set into a fully closed state.
[0040] For example, releasing the fuel shut valve 62, closing the
fuel shut valve 63, and raising the opening degree of the fuel
control valve 64 from the fully closed state cause an increase in a
supply flow rate of the startup fuel f1 to the fuel cavity 25 and
only the startup fuel f1 to be jetted from the fuel nozzles 21.
Conversely, releasing the fuel shut valve 63, closing the fuel shut
valve 62, and raising the opening degree of the fuel control valve
65 from the fully closed state cause an increase in a supply flow
rate of the main fuel f2 to the fuel cavity 25 and only the main
fuel f2 to be jetted from the fuel nozzles 21. Furthermore,
releasing both the fuel shut valves 62 and 63 and raising the
opening degrees of the fuel control valves 64 and 65 from the fully
closed states cause the startup fuel f1 and the main fuel f2 to be
mixed up in the fuel mixer 61 and a mixed gaseous fuel of the two
fuels to be jetted from the fuel nozzles 21 via the fuel cavity 25.
Moreover, raising the opening degree of the fuel control valve 66
from the fully closed state in a state of releasing the fuel shut
valve 63 causes an increase in the supply flow rate of the main
fuel f2 to the fuel cavity 26 and only the main fuel f2 to be
jetted from the fuel nozzles 22 and 23.
[0041] While a case in which the number of annular rows of air
holes is three is exemplarily illustrated in the present
embodiment, the number of annular rows of air holes may be two or
may be equal to or greater than four. Increasing the number of rows
enables the combustor 3 to be compatible with a large-capacity gas
turbine and improvement in operation controllability.
[0042] Furthermore, the combustor 3 is equipped with a controller
70 controlling the fuel shut valves 62 and 63 and the fuel control
valves 64 to 66. The controller 70 controls the fuel shut valves 62
and 63 and the fuel control valves 64 to 66 on the basis of a gas
turbine load detected by a sensor 71. In the present embodiment,
output electric power from the electric generator 6 or a rotation
speed of the turbine 4 is measured as the gas turbine load, and a
power meter or a rotation sensor can be used as the sensor 71.
Moreover, because of a proportional relationship between the gas
turbine load and a flow rate of the fuel, a flowmeter measuring a
supply flow rate of the fuel or an opening meter measuring the
opening degrees of the fuel control valves 64 to 66 can be used as
the sensor 71.
[0043] The controller 70 is a computer and configured with an input
interface, a read only memory (ROM) such as an erasable
programmable read only memory (EPROM), a random access memory
(RAM), a central processing unit (CPU), a timer, an output
interface, and the like. A detection signal output from the sensor
71 and an operation signal output from an input device (not
depicted) in response to an operator's operation are input to the
input interface. The ROM stores computing equations, programs, and
data necessary for an operation of the gas turbine plant 1
including the combustor 3. The RAM stores, for example, numerical
values in the middle of computing and data input from the input
device. The output interface outputs command signals to the fuel
shut valves 62 and 63, the fuel control valves 64 to 66, and the
other actuating device such as an inlet guide vane (IGV) provided
in the gas turbine plant 1 in response to commands from the
CPU.
[0044] The CPU executes control over the fuel shut valves 62 and
63, the fuel control valves 64 to 66, and the like on the basis of
the data input via the input interface in accordance with the
programs loaded from the ROM.
--Operations--
[0045] An operating method of the combustor 3 according to the
present embodiment will be described hereinafter. The operating
method described hereinafter is automatically executed by the
controller 70 in response to the gas turbine load detected by the
sensor 71. Alternatively, an operator can execute the operating
method by a manual operation as appropriate while monitoring the
gas turbine load. Flow rates of the startup fuel f1 and the main
fuel f2 are determined on the basis of the gas turbine load such as
the output electric power, and the opening degrees of the fuel
control valves 64, 65, and 66 are controlled in such a manner as to
supply the fuels at the flow rates in response to the gas turbine
load.
[0046] FIG. 3 is an explanatory diagram of the combustor operating
method (startup time) according to the first embodiment. An example
of the operating method at a startup time since ignition of the
startup fuel f1 until transition to a state of single firing of the
main fuel f2 will be described with reference to FIG. 3. In FIG. 3,
a horizontal axis represents the gas turbine load and the gas
turbine load is heavier as being closer to a right side.
Furthermore, an upper row of FIG. 3 depicts changes in the flow
rates of the startup fuel f1 and the main fuel f2, and a lower row
thereof depicts a change in a flow rate of the gaseous fuel
supplied to the inner fuel nozzles 21 and the outer fuel nozzles 22
and 23 along with burner schematic diagrams. An inner burner F1
depicted in the burner schematic diagrams is an inner
circumferential side circular burner configured with the fuel
nozzles 21, and an outer burner F2 is an outer circumferential side
toroidal burner configured with the fuel nozzles 22 and 23.
[0047] In the present embodiment, the controller 70 or the operator
executes the following four procedures (1) to (4) in a sequential
order to perform operations from ignition to a rated load.
[0048] (1) Supply the startup fuel f1 to the fuel nozzles 21 (inner
burner F1) in a state of not supplying the fuel to the fuel nozzles
22 and 23 (outer burner F2).
[0049] (2) Supply the main fuel f2 to the fuel nozzles 22 and 23 in
a state of continuing to supply the startup fuel f1 to the fuel
nozzles 21 (inner burner F1).
[0050] (3) Start to supply the main fuel f2 to the fuel nozzles
(inner burner F1) while continuing to supply the main fuel f2 to
the fuel nozzles 22 and 23 (outer burner F2), and change over the
fuel supplied to the fuel nozzles 21 from the startup fuel f1 to
the mixed gaseous fuel of the startup fuel f1 and the main fuel
f2.
[0051] (4) Stop to supply the startup fuel f1 to the fuel nozzles
21 (inner burner F1) and supply only the main fuel f2 to all the
fuel nozzles 21 to 23 (both of the inner burner F1 and the outer
burner F2).
[0052] Fuel supply states in the procedures (1) to (4) correspond
to burner schematic diagrams (1) to (4) of the same numbers
represented in the lower row of FIG. 3, respectively. Operations of
the valves in the procedures (1) to (4) will be described.
Procedure (1)
[0053] The startup motor 7 starts to rotate a gas turbine rotor,
and the controller 70 executes the procedure (1) when the gas
turbine load (for example, the rotation speed of the turbine 4 or
the output electric power from the electric generator 6) rises up
to a set value L0 that satisfies an ignitable condition. In the
procedure (1), the controller 70 outputs signals S2 and S4 (FIG. 1)
to the fuel shut valve 62 and the fuel control valve 64, and
releases the fuel shut valve 62 and opens the fuel control valve 64
to raise the opening degree of the fuel control valve 64 at, for
example, a specified increasing rate. The startup fuel f1 is
thereby jetted from the fuel nozzles 21 of the inner burner F1 and
ignited, the startup fuel f1 increases at a predetermined
increasing rate, and the gas turbine load rises. During this time,
the controller 70 leaves the fuel shut valve 63 and the fuel
control valves 65 and 66 closed. In a case of operator's regulating
the fuel flow rates, the operator manually operates the opening
degrees of the fuel shut valves 62 and 63 and the fuel control
valves 64 to 66 using an operation device (not depicted) as
described above.
Procedure (2)
[0054] When the gas turbine load rises up to a first set value L1
(>L0), the controller 70 outputs signals S2, S3, S4, and S6
(FIG. 1) to the fuel shut valves 62 and 63 and the fuel control
valves 64 to 66 to execute the procedure (2). In the procedure (2),
the controller 70 releases the fuel shut valves 62 and 63, and
opens the fuel control valve 66 to raise the opening degree of the
fuel control valve 66 at, for example, a specified increasing rate
while maintaining the opening degree of the fuel control valve 64.
The main fuel f2 thereby starts to be jetted from the fuel nozzles
22 and 23 of the outer burner F2 in a state of maintaining an
injection quantity of the startup fuel f1 from the fuel nozzles 21
of the inner burner F1, and the main fuel f2 is ignited with a
flame formed by the startup fuel f1 as a source of fire. The main
fuel f2 further increases at a predetermined increasing rate, and
the gas turbine load rises. During this time, the controller 70
leaves the fuel control valve 65 closed. In the case of operator's
regulating the fuel flow rates, the operator manually operates the
opening degrees of the fuel shut valves 62 and 63 and the fuel
control valves 64 to 66 using the operation device (not depicted)
as described above.
Procedure (3)
[0055] When the gas turbine load rises to a second set value L2
(>L1), the controller 70 outputs the signals S2 to S6 (FIG. 1)
to the fuel shut valves 62 and 63 and the fuel control valves 64 to
66 to execute the procedure (3). In the procedure (3), the
controller 70 opens the fuel control valve 65 in a state of
releasing the fuel shut valves 62 and 63, and lowers the opening
degree of the fuel control valve 64 down to zero while increasing
the opening degrees of the fuel control valves 65 and 66 at, for
example, a specified increasing rate. The mixed gaseous fuel of the
startup fuel f1 and the main fuel f2 thereby starts to be jetted
from the fuel nozzles 21 of the inner burner F1, a main fuel
concentration of the mixed gaseous fuel increases, and an injection
quantity of the main fuel f2 from the fuel nozzles 22 and 23 of the
outer burner F2 increases. The main fuel f2 starting to be jetted
from the fuel nozzles 21 is stably burned together with the startup
fuel f1. During this time, the flow rate of the startup fuel f1
decreases but the gas turbine load further rises with the increase
of the main fuel f2. In the case of operator's regulating the fuel
flow rates, the operator manually operates the opening degrees of
the fuel shut valves 62 and 63 and the fuel control valves 64 to 66
using the operation device (not depicted) as described above.
Procedure (4)
[0056] The gas turbine load is designed to reach a third set value
L3 (>L2) before a supply quantity of the main fuel f2 increases,
the opening degree of the fuel control valve 64 falls down to zero,
and supply of the startup fuel f1 stops. In other words, when the
gas turbine load rises up to the third set value L3, the controller
70 closes the fuel shut valve 62 and the fuel control valve 64 and
stops to supply the startup fuel f1 to the inner fuel nozzles 21. A
firing state thereby transitions to the state of single firing of
the main fuel f2 in which only the main fuel f2 is jetted from all
of the inner and outer fuel nozzles 21 to 23. Subsequently, the
controller 70 outputs the signals S3, S5, and S6 (FIG. 1) to the
fuel shut valve 63 and the fuel control valves 65 and 66, and
raises the opening degrees of the fuel control valves 65 and 66
(for example, a total opening area) at, for example, a specified
increasing rate in a state of releasing the fuel shut valve 63. As
a result, the gas turbine load rises up to a rated value LR and a
startup operation is over. In the case of operator's regulating the
fuel flow rates, the operator manually operates the opening degrees
of the fuel shut valves 62 and 63 and the fuel control valves 64 to
66 using the operation device (not depicted) as described
above.
[0057] According to this startup method, it is possible to ensure
ignition of the main fuel f2 using the flame formed by igniting the
startup fuel f1, and stably and smoothly change over from the
co-firing of the startup fuel f1 and the main fuel f2 to the single
firing of the main fuel f2. It is to be noted that while the case
of transitioning the gas turbine load to the rated load in the
state of single firing of the main fuel f2 is taken by way of
example in the present embodiment, some gas turbine plants
transition the gas turbine load to the rated load in the state of
co-firing of the startup fuel f1 and the main fuel f2. In that
case, the controller 70 can be configured to exercise control to
transition the gas turbine load to the rated load by executing the
procedure (2) or (3). In this case, it is possible to omit the
procedures (3) and (4) or the procedure (4).
[0058] FIG. 4 is an explanatory diagram of a combustor operating
method (stop time) according to the first embodiment. An example of
the operating method at a stop time since the state of the single
firing of the main fuel f2 until extinguishing will be described
with reference to FIG. 4. In FIG. 4, a horizontal axis represents
the gas turbine load and the gas turbine load is lighter as being
closer to a right side. Furthermore, an upper row of FIG. 4 depicts
changes in the flow rates of the startup fuel f1 and the main fuel
f2, and a lower row thereof depicts a change in the flow rate of
the gaseous fuel supplied to the inner fuel nozzles 21 and the
outer fuel nozzles 22 and 23 along with burner schematic
diagrams.
[0059] In the present embodiment, the controller 70 or the operator
executes the following four procedures (5) to (8) in a sequential
order to perform operations from the rated load to extinguishing of
the fuel.
[0060] (5) Lower the supply quantity of the main fuel f2 to the
fuel nozzles 22 and 23 (outer burner F2) in a state of supplying
only the main fuel f2 to all of the fuel nozzles 21 to 23 (both of
the inner burner F1 and the outer burner F2).
[0061] (6) Start to supply the startup fuel f1 to the fuel nozzles
21 (inner burner F1) while continuing to supply the main fuel f2 to
the fuel nozzles 22 and 23 (outer burner F2), and change over the
fuel supplied to the fuel nozzles 21 from the main fuel f2 to the
mixed gaseous fuel of the startup fuel f1 and the main fuel f2.
[0062] (7) Reduce the supply quantity of the main fuel f2 to the
fuel nozzles 22 and 23 (outer burner F2) in a state of stopping to
supply the main fuel f2 to the fuel nozzles 21 (inner burner F1)
and supplying only the startup fuel f1 to the fuel nozzles 21
(inner burner F1).
[0063] (8) Stop to supply the main fuel f2 to the fuel nozzles 22
and 23 (outer burner F2), and reduce the supply flow rate of the
startup fuel f1 to the fuel nozzles 21 (inner burner F1) to
extinguish the startup fuel f1 while supplying the startup fuel f1
only to the fuel nozzles 21 (inner burner F1).
[0064] Fuel supply states in the procedures (5) to (8) correspond
to burner schematic diagrams (5) to (8) of the same numbers
represented in the lower row of FIG. 4, respectively. Operations of
the valves in the procedures (5) to (8) will be described.
Procedure (5)
[0065] When a stop signal is input to the controller 70 from the
operation device (not depicted), the controller 70 outputs the
signals S3, S5, and S6 (FIG. 1) to the fuel shut valve 63 and the
fuel control valves 65 and 66 to execute the procedure (5). In the
procedure (5), the controller 70 lowers the opening degree of the
fuel control valve 66 while raising the opening degree of the fuel
control valve 65 in a state of releasing the fuel shut valve 63,
and lowers a total supply flow rate of the main fuel f2 at, for
example, a specified increasing rate. During this time, the
controller 70 leaves the fuel shut valve 62 and the fuel control
valve 64 closed. In the case of operator's regulating the fuel flow
rates, the operator manually operates the opening degrees of the
fuel shut valves 62 and 63 and the fuel control valves 64 to 66
using the operation device (not depicted) as described above.
Procedure (6)
[0066] When the gas turbine load lowers from the rated load LR to a
fourth set value L4 (<LR), the controller 70 outputs the signals
S2 to S6 (FIG. 1) to the fuel shut valves 62 and 63 and the fuel
control valves 64 to 66 to execute the procedure (6). In the
procedure (6), the controller 70 opens the fuel control valve 64
while lowering the opening degree of the fuel control valve 66 in a
state of releasing the fuel shut valves 62 and 63, and lowers the
opening degree of the fuel control valve 65 down to zero while
increasing the opening degree of the fuel control valve 64 at, for
example, a specified increasing rate. The mixed gaseous fuel of the
startup fuel f1 and the main fuel f2 thereby starts to be jetted
from the fuel nozzles 21 of the inner burner F1, a startup fuel
concentration of the mixed gaseous fuel increases and the injection
quantity of the main fuel f2 from the fuel nozzles 22 and 23 of the
outer burner F2 decreases, and the load falls. A burning velocity
falls by start of jetting of the startup fuel f1 from the fuel
nozzles 21. In the case of operator's regulating the fuel flow
rates, the operator manually operates the opening degrees of the
fuel shut valves 62 and 63 and the fuel control valves 64 to 66
using the operation device (not depicted) as described above.
Procedure (7)
[0067] When the gas turbine load further falls down to a fifth set
value L5 (<L4), the controller 70 outputs the signals S2, S3, S4
and S6 (FIG. 1) to the fuel shut valves 62 and 63 and the fuel
control valves 64 and 66 to execute the procedure (7). In the
procedure (7), the controller 70 lowers the opening degree of the
fuel control valve 66 at, for example, a specified increasing rate
while maintaining the opening degree of the fuel control valve 64
in a state of releasing the fuel shut valves 62 and 63. The
injection quantity of the main fuel f2 from the fuel nozzles 22 and
23 of the outer burner F2 thereby decreases and the gas turbine
load falls in a state of maintaining the injection quantity of the
startup fuel f1 from the fuel nozzles 21 of the inner burner F1.
During this time, the fuel control valve 65 is closed and supply of
the main fuel f2 to the fuel nozzles 21 of the inner burner F1 is
stopped, and the firing state is closer to the single firing of the
startup fuel f1 with a reduction in the supply quantity of the main
fuel f2. In the case of operator's regulating the fuel flow rates,
the operator manually operates the opening degrees of the fuel shut
valves 62 and 63 and the fuel control valves 64 to 66 using the
operation device (not depicted) as described above.
Procedure (8)
[0068] The gas turbine load is designed to reach a sixth set value
L6 (<L5) before the supply quantity of the main fuel f2 is equal
to zero. In other words, when the gas turbine load falls down to
the sixth set value L6, the controller 70 closes the fuel shut
valve 63 and the fuel control valves 65 and 66 to stop to supply
the main fuel f2 to the fuel nozzles 21 to 23. The firing state
thereby transitions to the state of the single firing of the
startup fuel f1 in which only the startup fuel f1 is jetted from
the inner fuel nozzles 21. Subsequently, the controller 70 outputs
the signals S2 and S4 (FIG. 1) to the fuel shut valve 62 and the
fuel control valve 64, and lowers the opening degree of the fuel
control valve 64 to zero at, for example, a specified increasing
rate in a state of releasing the fuel shut valve 62. In this
course, the burner 8 is extinguished and a stop operation is over.
In the case of operator's regulating the fuel flow rates, the
operator manually operates the opening degrees of the fuel shut
valves 62 and 63 and the fuel control valves 64 to 66 using the
operation device (not depicted) as described above.
[0069] According to this startup method, the firing state
transitions to the state of the single firing of the startup fuel
f1 before extinguishing; thus, it is possible to avoid stagnation
of the main fuel f2 in the downstream turbine 4 while the main fuel
f2 is unburned.
--Advantages--
[0070] FIG. 5 is an explanatory diagram of advantages of the
present invention. In the present embodiment, the startup fuel f1
such as the natural gas is ignited and then the main fuel f2 that
is the hydrogen content fuel is supplied, thereby making it
possible to ensure ignition of the main fuel f2 to prevent the main
fuel f2 from being emitted from the combustor 3 while the main fuel
f2 remains unburned. A reason for the above will be described with
reference to FIG. 5. FIG. 5 represents an outline of flames formed
downstream of the burner. First, the startup fuel f1 is supplied to
the inner fuel nozzles 21, and a central flame 121 of the startup
fuel f1 is formed in a burner central portion downstream of the
inner air holes 51. Next, the main fuel f2 is supplied to the outer
fuel nozzles 22 and 23, and the mixed gaseous fuel of the main fuel
f2 and the compressed air a2 is jetted from the outer air holes 52
and 53 to the combustion chamber 5. The mixed gaseous fuel
containing the main fuel f2 and jetted from the outer air holes 52
and 53 to the combustion chamber 5 is reliably ignited by heat of
the previously formed central flame 121, and a surrounding flame
122 by the main fuel f2 is formed around the central flame 121. It
is possible to ensure ignition of the main fuel f2 using the
previously formed central flame 121 by the startup fuel f1 in this
way, and to prevent the main fuel f2 from being emitted from the
combustor 3 and stagnating within the downstream turbine 4 while
the main fuel f2 remains unburned.
[0071] At this time, the fuel mixer 61 to which each of or both of
the startup fuel f1 and the main fuel f2 can be supplied is
connected to the inner fuel nozzles 21, thereby making it possible
to inject the startup fuel f1, the main fuel f2, and the mixed
gaseous fuel of the startup fuel f1 and the main fuel f2 from the
same fuel nozzles 21 (same injection ports). It is thereby possible
to inject the main fuel f2 also from the fuel nozzles 21 (injection
ports) used to inject the startup fuel f1 in a case of injecting
and igniting the startup fuel f1 and then transitioning a firing
operation to an operation of the single firing of the main fuel f2.
It is possible to supply the main fuel f2 also to a formation zone
of the central flame 121 by the startup fuel f1 and appropriately
maintain dispersibility of the gaseous fuel even after
transitioning to the state of the single firing of the main fuel
f2.
[0072] As described so far, according to the present embodiment, it
is possible to stably ignite the hydrogen content fuel using the
gaseous fuel that does not contain hydrogen and enhance the
dispersibility of the hydrogen content fuel. Since a gas turbine
power generation plant can be made stable use of by the hydrogen
content fuel, it is possible to contribute to mitigation of global
warming. Furthermore, since combustion stability can be ensured by
making use of byproduct gas produced in an iron works or an oil
refinery as the main fuel f2, it is possible to contribute to
utilization of natural resources and reduction of power generation
cost.
[0073] Moreover, since the supply of the main fuel f2 is stopped
and the firing state is transitioned to the state of the single
firing of the startup fuel f1 before extinguishing, it is possible
to prevent flame off before stop of the supply of the main fuel f2
and to avoid stagnation of the main fuel f2 within the downstream
turbine 4 while the main fuel f2 remains unburned even in the stop
operation.
Second Embodiment
[0074] FIG. 6 is a schematic configuration diagram of a gas turbine
plant configured with a gas turbine combustor according to a second
embodiment. FIG. 6 corresponds to FIG. 1 according to the first
embodiment. In FIG. 6, similar elements to those in the first
embodiment are denoted by the same reference characters as those in
FIG. 1 and description thereof is omitted. The present embodiment
differs from the first embodiment in that injection ports of inner
fuel nozzles 21A and outer fuel nozzles 22A are open to inner wall
surfaces of air holes of the air hole plate 20.
[0075] In the present embodiment, injection ports 701 of the fuel
nozzles 21A are open to inner walls of the air holes 51, and
injection ports 702 and 703 of the fuel nozzles 22A are open to
inner walls of the air holes 52 and 53. The communication duct 68
is connected to the fuel nozzles 21A and the main fuel pipe 60 is
connected to the fuel nozzles 22A. Other configurations are similar
to those according to the first embodiment.
[0076] Even with such a lean combustion type burner configuration,
it is possible to obtain similar advantages to those of the first
embodiment by similarly controlling the fuels.
Third Embodiment
--Configurations--
[0077] FIG. 7 is a schematic configuration diagram of a gas turbine
plant configured with a gas turbine combustor according to a third
embodiment of the present invention. FIG. 8 depicts a burner
provided in the gas turbine combustor according to the third
embodiment of the present invention, the burner being viewed from a
combustion chamber. FIGS. 7 and 8 correspond to FIGS. 1 and 2 of
the first embodiment. In FIGS. 7 and 8, similar elements to those
in the first embodiment are denoted by the same reference
characters as those in FIG. 1 and description thereof is omitted.
The present embodiment differs from the first embodiment in that
the outer fuel nozzles 22 and 23 are divided into a plurality of
(three in the present embodiment) nozzle groups, and in that the
main fuel pipe 60 branches off to a plurality of (three in the
present embodiment) pipes that are connected to the corresponding
nozzle groups.
[0078] In the present embodiment, the outer fuel nozzles 22 and 23
and the air holes 52 and 53 are demarcated into a plurality of
zones X1 to X3 in a circumferential direction, and a first nozzle
group belongs to the zone X1, a second nozzle group belongs to the
zone X2, and a third nozzle group belongs to the zone X3.
Furthermore, in the present embodiment, the fuel cavity 26 that
distributes the main fuel f2 to the outer fuel nozzles 22 and 23 is
also divided into a plurality of (three in the present embodiment)
fuel cavities 26a to 26c. The fuel cavity 26a is connected to the
fuel nozzles 22 and 23 configuring the first nozzle group. The fuel
cavity 26b is connected to the fuel nozzles 22 and 23 configuring
the second nozzle group. The fuel cavity 26c is connected to the
fuel nozzles 22 and 23 configuring the third nozzle group.
[0079] Moreover, in the present embodiment, the main fuel pipe 60
branches off to a plurality of (three in the present embodiment)
branch pipes 60a to 60c. The branch pipe 60a is connected to the
fuel cavity 26a, the branch pipe 60b is connected to the fuel
cavity 26b, and the branch pipe 60c is connected to the fuel cavity
26c. A fuel control valve is not provided in the main fuel pipe 60
(portion before branching off to the branch pipes 60a to 60c). In
the present embodiment, a fuel control valve 66a is provided in the
branch pipe 60a, a fuel control valve 66b is provided in the branch
pipe 60b, and a fuel control valve 66c is provided in the branch
pipe 60c. The fuel control valves 66a to 66c are identical to the
fuel control valve 66 according to the first embodiment.
[0080] The present embodiment is similar to the first embodiment in
other respects. It is noted that a burner configured in such a
manner that the injection ports of the fuel nozzles are open to the
inner wall surfaces of the air holes is also applicable to the
present embodiment similarly to the second embodiment. The number
of nozzle groups is not limited to three and may be two or more.
For example, the number of nozzle groups may be equal to or greater
than four or may be two. Increasing the number of nozzle groups
enables the combustor 3 to be compatible with a large-capacity gas
turbine and improvement in operation controllability. Furthermore,
the nozzle groups into which the fuel nozzles 22 and 23 are divided
can be set not in the circumferential direction but in a radial
direction (that is, as annular rows).
--Operations--
[0081] FIG. 9 is an explanatory diagram of a combustor operating
method (startup time) according to the third embodiment. FIG. 9
corresponds to FIG. 3 according to the first embodiment. An example
of the operating method at the startup time since ignition of the
startup fuel f1 until transition to the state of the single firing
of the main fuel f2 will be described with reference to FIG. 9. In
FIG. 9, a horizontal axis represents the gas turbine load and the
gas turbine load is heavier as being closer to a right side.
Furthermore, an upper row of FIG. 9 depicts changes in the flow
rates of the startup fuel f1 and the main fuel f2, and a lower row
thereof depicts a change in the flow rate of the gaseous fuel
supplied to the inner fuel nozzles 21 and the nozzle groups of the
outer fuel nozzles 22 and 23 along with burner schematic diagrams.
The inner burner F1 depicted in the burner schematic diagrams is
the inner circumferential side circular burner configured with the
fuel nozzles 21. An outer burner F2a is a fan-shaped burner
configured with the fuel nozzles 22 and 23 in the first nozzle
group. An outer burner F2b is a fan-shaped burner configured with
the fuel nozzles 22 and 23 in the second nozzle group, and an outer
burner F2c is a fan-shaped burner configured with the fuel nozzles
22 and 23 in the third nozzle group.
[0082] Startup procedures according to the present embodiment are
similar to those according to the first embodiment except that the
procedure (2) in the four procedures (1) to (4) described in the
first embodiment is divided into three stages of procedures (2a) to
(2c). In the present embodiment, the procedures (1), (3), and (4)
are similar to those according to the first embodiment and
description thereof is, therefore, omitted, and the procedures (2a)
to (2c) will be described hereinafter. Upon completion of the
procedure (1), the following procedures (2a) to (2c) are executed
in a sequential order. Upon completion of the procedure (2c), the
procedures (3) and (4) are executed similarly to the first
embodiment. It is noted that while the three fuel control valves
66a to 66c are provided for the outer burners F2a to F2c in the
present embodiment, the fuel control valves 66a to 66c are
similarly controlled in the procedures (3) and (4).
Procedure (2a)
[0083] When the gas turbine load rises up to a first set value L1a
(>L0) after execution of the procedure (1), the controller 70
outputs signals S2, S3, S4, and S6a (FIG. 7) to the fuel shut
valves 62 and 63 and the fuel control valves 64 and 66a to execute
the procedure (2a). In the procedure (2a), the controller 70
releases the fuel shut valves 62 and 63, and opens the fuel control
valve 66a to raise the opening degree of the fuel control valve 66a
at, for example, a specified increasing rate while maintaining the
opening degree of the fuel control valve 64. The main fuel f2
thereby starts to be jetted from the fuel nozzles 22 and 23 of the
outer burner F2a in the state of maintaining the injection quantity
of the startup fuel f1 from the fuel nozzles 21 of the inner burner
F1, and the main fuel f2 is ignited with the flame formed by the
startup fuel f1 as the source of fire. The main fuel f2 further
increases at a predetermined increasing rate, and the gas turbine
load rises. During this time, the controller 70 leaves the fuel
control valves 65, 66b, and 66c closed. In the case of operator's
regulating the fuel flow rates, the operator manually operates the
opening degrees of the fuel shut valves 62 and 63 and the fuel
control valves 64, 65, and 66a to 66c using the operation device
(not depicted) as described above.
Procedure (2b)
[0084] When the gas turbine load rises up to a set value L1b
(>L1a), the controller 70 outputs signals S2, S3, S4, S6a, and
S6b (FIG. 7) to the fuel shut valves 62 and 63 and the fuel control
valves 64, 66a, and 66b to execute the procedure (2b). In the
procedure (2b), the controller 70 releases the fuel shut valves 62
and 63, and newly opens the fuel control valve 66b to raise the
opening degree of the fuel control valve 66b at, for example, a
specified increasing rate while maintaining the opening degrees of
the fuel control valves 64 and 66a. The main fuel f2 starting to be
jetted from the fuel nozzles 22 and 23 of the outer burner F2b is
thereby smoothly ignited, a supply zone of the main fuel f2 expands
and the supply quantity of the main fuel f2 further increases, and
the gas turbine load rises. During this time, the controller 70
leaves the fuel control valves 65 and 66c closed. In the case of
operator's regulating the fuel flow rates, the operator manually
operates the opening degrees of the fuel shut valves 62 and 63 and
the fuel control valves 64, 65, and 66a to 66c using the operation
device (not depicted) as described above.
Procedure (2c)
[0085] When the gas turbine load rises up to a set value L1c
(L1b<L1c<L2), the controller 70 outputs signals S2, S3, S4,
S6a to S6c (FIG. 7) to the fuel shut valves 62 and 63 and the fuel
control valves 64, 66a to 66c to execute the procedure (2c). In the
procedure (2c), the controller 70 releases the fuel shut valves 62
and 63, and newly opens the fuel control valve 66c to raise the
opening degree of the fuel control valve 66c at, for example, a
specified increasing rate while maintaining the opening degrees of
the fuel control valves 64, 66a, and 66b. The main fuel f2 starting
to be jetted from the fuel nozzles 22 and 23 of the outer burner
F2c is thereby smoothly ignited, the supply zone of the main fuel
f2 expands and the supply quantity of the main fuel f2 further
increases, and the gas turbine load rises. During this time, the
controller 70 leaves the fuel control valve 65 closed. In the case
of operator's regulating the fuel flow rates, the operator manually
operates the opening degrees of the fuel shut valves 62 and 63 and
the fuel control valves 64, 65, and 66a to 66c using the operation
device (not depicted) as described above.
[0086] FIG. 10 is an explanatory diagram of a combustor operating
method (stop time) according to the third embodiment. FIG. 10
corresponds to FIG. 4 according to the first embodiment. An example
of the operating method at the stop time since the state of the
single firing of the main fuel f2 until extinguishing will be
described with reference to FIG. 10. In FIG. 10, a horizontal axis
represents the gas turbine load and the gas turbine load is lighter
as being closer to a right side. Furthermore, an upper row of FIG.
10 depicts changes in the flow rates of the startup fuel f1 and the
main fuel f2, and a lower row thereof depicts a change in the flow
rate of the gaseous fuel supplied to the inner fuel nozzles 21 and
the nozzle groups of the outer fuel nozzles 22 and 23 along with
burner schematic diagrams.
[0087] Stop procedures according to the present embodiment are
similar to those according to the first embodiment except that the
procedure (7) in the four procedures (5) to (8) described in the
first embodiment is divided into three stages of procedures (7a),
(7b), and (7c). In the present embodiment, the procedures (5), (6),
and (8) are similar to those according to the first embodiment and
description thereof is, therefore, omitted, and the procedures
(7c), (7b), and (7a) will be described hereinafter. Upon completion
of the procedures (5) and (6), the following procedures (7c), (7b),
and (7a) are executed in a sequential order. Upon completion of the
procedure (7a), the procedure (8) is executed similarly to the
first embodiment. It is noted that while the three fuel control
valves 66a to 66c are provided for the outer burners F2a to F2c in
the present embodiment, the fuel control valves 66a to 66c are
similarly controlled in the procedures (5) and (6).
Procedure (7c)
[0088] When the gas turbine load falls down to a fifth set value
L5c (<L4) after execution of the procedure (6), the controller
70 outputs the signals S2, S3, S4, and S6a to S6c (FIG. 7) to the
fuel shut valves 62 and 63 and the fuel control valves 64 and 66a
to 66c to execute the procedure (7c). In the procedure (7c), the
controller 70 lowers the opening degree of the fuel control valve
66c down to zero at, for example, a specified increasing rate while
maintaining the opening degrees of the fuel control valves 64, 66a,
and 66b in the state of releasing the fuel shut valves 62 and 63.
The injection quantity of the main fuel f2 from the outer burner
F2c thereby decreases and the gas turbine load falls in a state of
maintaining the injection quantity of the startup fuel f1 from the
inner burner F1 and injection quantities of the main fuel f2 from
the outer burners F2a and F2b. During this time, the fuel control
valve 65 is closed and the supply of the main fuel f2 to the fuel
nozzles 21 of the inner burner F1 is stopped. In the case of
operator's regulating the fuel flow rates, the operator manually
operates the opening degrees of the fuel shut valves 62 and 63 and
the fuel control valves 64 to 66 using the operation device (not
depicted) as described above.
Procedure (7b)
[0089] When the gas turbine load falls down to a set value L5b
(<L5c), the controller 70 outputs the signals S2, S3, S4, S6a,
and S6b (FIG. 7) to the fuel shut valves 62 and 63 and the fuel
control valves 64, 66a, and 66b to execute the procedure (7b). In
the procedure (7b), the controller 70 lowers the opening degree of
the fuel control valve 66b down to zero at, for example, a
specified increasing rate while maintaining the opening degrees of
the fuel control valves 64 and 66a in the state of releasing the
fuel shut valves 62 and 63. The injection quantity of the main fuel
f2 from the outer burner F2b thereby decreases and the gas turbine
load further falls in a state of maintaining the injection quantity
of the startup fuel f1 from the inner burner F1 and the injection
quantity of the main fuel f2 from the outer burner F2a. During this
time, the controller 70 leaves the fuel control valves 65 and 66c
closed. In the case of operator's regulating the fuel flow rates,
the operator manually operates the opening degrees of the fuel shut
valves 62 and 63 and the fuel control valves 64 to 66 using the
operation device (not depicted) as described above.
Procedure (7a)
[0090] When the gas turbine load falls down to a set value L5a
(L6<L5a<L5b), the controller 70 outputs the signals S2, S3,
S4, and S6a (FIG. 7) to the fuel shut valves 62 and 63 and the fuel
control valves 64 and 66a to execute the procedure (7a). In the
procedure (7a), the controller 70 lowers the opening degree of the
fuel control valve 66a down to zero at, for example, a specified
increasing rate while maintaining the opening degree of the fuel
control valves 64 in the state of releasing the fuel shut valves 62
and 63. The injection quantity of the main fuel f2 from the outer
burner F2a thereby decreases and the gas turbine load further falls
in a state of maintaining the injection quantity of the startup
fuel f1 from the inner burner F1. During this time, the controller
70 leaves the fuel control valves 65, 66b, and 66c closed. In the
case of operator's regulating the fuel flow rates, the operator
manually operates the opening degrees of the fuel shut valves 62
and 63 and the fuel control valves 64 to 66 using the operation
device (not depicted) as described above.
--Advantages--
[0091] The present embodiment can obtain similar advantages to
those of the first embodiment. Furthermore, dividing the outer fuel
nozzles 22 and 23 into the plurality of nozzle groups, and
executing start and stop of the supply of the main fuel f2 per
nozzle group to perform the ignition of the main fuel f2 and the
like stepwise make it possible to further ensure suppression of the
emission of the unburned main fuel f2.
Fourth Embodiment
--Configurations--
[0092] FIG. 11 is a schematic configuration diagram of a gas
turbine plant configured with a gas turbine combustor according to
a fourth embodiment of the present invention. FIG. 12 depicts a
burner provided in the gas turbine combustor according to the
fourth embodiment of the present invention, the burner being viewed
from a combustion chamber. FIGS. 11 and 12 correspond to FIGS. 1
and 2 of the first embodiment. In FIGS. 11 and 12, similar elements
to those in the first embodiment are denoted by the same reference
characters as those in FIGS. 1 and 2 and description thereof is
omitted. The present embodiment differs from the first embodiment
in that the combustor 3 is configured with a multi-burner
configured with a plurality of burners.
[0093] The combustor 3 according to the present embodiment is
configured with a pilot burner 31 and a plurality of (six in the
present embodiment) main burners 32, and the pilot burner 31 and
the main burners 32 are disposed in such a manner that surroundings
of one pilot burner 31 disposed at a center are surrounded by the
plurality of main burners 32. In the present embodiment, a case of
applying a burner structure according to the first embodiment to
each of the pilot burner 31 and the main burners 32 is exemplarily
illustrated. It is to be noted that the burner 8 according to the
first, second, or third embodiment can be applied to each of the
pilot burner 31 and the main burners 32 as appropriate. For
example, the burner 8 according to any of the first to third
embodiments can be uniformly used as each of the pilot burner 31
and the main burners 32, or a mixture of the burners 8 according to
the first to third embodiments can be used as the pilot burner 31
and the main burners 32 as appropriate. The air hole plate 20 can
be shared among the pilot burner 31 and the plurality of main
burners 32 (the air holes 51 to 53 of each burner can be formed in
one air hole plate 20).
[0094] As for the fuel supplying system 200, the communication duct
68 branches off to a plurality of (three in the present embodiment)
branch pipes 68A to 68C. The branch pipe 68A is connected to the
inner fuel nozzles 21 (fuel cavity 25) of the pilot burner 31. The
branch pipe 68B is connected to the inner fuel nozzles 21 (fuel
cavities 25) of half of the main burners 32, and the branch pipe
68C is connected to the inner fuel nozzles 21 (fuel cavities 25) of
the remaining main burners 32. Furthermore, a fuel control valve
65A is provided in the branch pipe 68A, a fuel control valve 65B is
provided in the branch pipe 68B, and a fuel control valve 65C is
provided in the branch pipe 68C. The fuel control valves 65A to 65C
are identical to, for example, the fuel control valve 65.
[0095] Moreover, in the present embodiment, the main fuel pipe 60
branches off to a plurality of (three in the present embodiment)
branch pipes 60A to 60C. The branch pipe 60A is connected to the
outer fuel nozzles 22 and 23 (fuel cavity 26) of the pilot burner
31. The branch pipe 60B is connected to the outer fuel nozzles 22
and 23 (fuel cavities 26) of half of the main burners 32, and the
branch pipe 60C is connected to the outer fuel nozzles 22 and 23
(fuel cavities 26) of the remaining main burners 32. A fuel control
valve is not provided in the main fuel pipe 60 (portion before
branching off to the branch pipes 60A to 60C). In the present
embodiment, a fuel control valve 66A is provided in the branch pipe
60A, a fuel control valve 66B is provided in the branch pipe 60B,
and a fuel control valve 66C is provided in the branch pipe 60C.
The fuel control valves 66A to 66C are identical to the fuel
control valve 66 according to the first embodiment.
[0096] The present embodiment is similar to the first, second, or
third embodiment in other respects.
--Operations--
[0097] FIG. 13 is an explanatory diagram of a combustor operating
method (startup time) according to the fourth embodiment. FIG. 13
corresponds to FIG. 3 according to the first embodiment. An example
of the operating method at the startup time since ignition of the
startup fuel f1 until transition to the state of the single firing
of the main fuel f2 will be described with reference to FIG. 13. In
FIG. 13, a horizontal axis represents the gas turbine load and the
gas turbine load is heavier as being closer to a right side.
Furthermore, an upper row of FIG. 13 depicts changes in the flow
rates of the startup fuel f1 and the main fuel f2, and a lower row
thereof depicts a change in the flow rate of the gaseous fuel
supplied to the inner fuel nozzles 21 and the outer fuel nozzles 22
and 23 of the pilot burner 31 and the main burners 32 along with
burner schematic diagrams. An inner burner F11 depicted in the
burner schematic diagrams is an inner burner (corresponding to the
fuel nozzles 21) of the pilot burner 31, and an outer burner F12 is
an outer burner (corresponding to the fuel nozzles 22 and 23) of
the pilot burner 31. In addition, as for the main burners 32, it is
assumed that three alternate main burners 32 in the circumferential
direction belong to a first group and that the remaining three main
burners 32 belong to a second group. An inner burner F21 is an
inner burner (corresponding to the fuel nozzles 21) of the main
burners 32 in the first group, and an outer burner F22 is an outer
burner (corresponding to the fuel nozzles 22 and 23) of the main
burners 32 in the first group. An inner burner F31 is an inner
burner (corresponding to the fuel nozzles 21) of the main burners
32 in the second group, and an outer burner F32 is an outer burner
(corresponding to the fuel nozzles 22 and 23) of the main burners
32 in the second group.
[0098] Startup procedures according to the present embodiment are
similar to those according to the first embodiment except that the
procedure (1) in the four procedures (1) to (4) described in the
first embodiment is divided into two stages of procedures (1A) and
(1B). The procedures (1A) and (1B) will be described hereinafter.
Upon completion of the following procedures (1A) and (1B), the
procedures (2) to (4) are executed similarly to the first
embodiment. It is noted that while the three fuel control valves
65A to 65C are provided for the startup fuel f1 in the present
embodiment, the fuel control valves 65A to 65C are similarly
controlled in the procedures (2) to (4). Likewise, while the three
fuel control valves 66A to 66C are provided for the main fuel f2,
the fuel control valves 66A to 66C are similarly controlled in the
procedures (2) to (4).
Procedure (1A)
[0099] The startup motor 7 starts to rotate the gas turbine rotor,
and the controller 70 executes the procedure (1A) when the gas
turbine load rises up to a set value L0A that satisfies an
ignitable condition. In the procedure (1A), the controller 70
outputs signals S2, S4, S5A, and S5B (FIG. 11) to the fuel shut
valve 62 and the fuel control valves 64, 65A, and 65B, and releases
the fuel shut valve 62 and opens the fuel control valves 64, 65A,
and 65B to raise the opening degrees of the fuel control valves 64,
65A, and 65B at, for example, a specified increasing rate. The
startup fuel f1 is thereby jetted from the inner burners F11 and
F21 and ignited, the startup fuel f1 increases at a predetermined
increasing rate, and the gas turbine load rises. During this time,
the controller 70 leaves the fuel shut valve 63 and the fuel
control valves 65, 65C and 66A to 66C closed. In the case of
operator's regulating the fuel flow rates, the operator manually
operates the opening degrees of the fuel shut valves 62 and 63 and
the fuel control valves 64, 65, 65A to 65C, and 66A to 66C using
the operation device (not depicted) as described above.
Procedure (1B)
[0100] When the gas turbine load rises up to a set value L0B
(L0A<L0B<L1), the controller 70 executes the procedure (1B).
In the procedure (1B), the controller 70 outputs signals S2, S4,
and S5A to S5C (FIG. 11) to the fuel shut valve 62 and the fuel
control valves 64 and 65A to 65C, newly opens the fuel control
valve 65C, and raises the opening degrees of the fuel control
valves 64 and 65A to 65C at, for example, a specified increasing
rate. The startup fuel f1 is thereby jetted from the inner burners
F11 to F31, the startup fuel f1 increases at a predetermined
increasing rate, and the gas turbine load rises. During this time,
the controller 70 leaves the fuel shut valve 63 and the fuel
control valves 65 and 66A to 66C closed. In the case of operator's
regulating the fuel flow rates, the operator manually operates the
opening degrees of the fuel shut valves 62 and 63 and the fuel
control valves 64, 65, 65A to 65C, and 66A to 66C using the
operation device (not depicted) as described above.
[0101] FIG. 14 is an explanatory diagram of a combustor operating
method (stop time) according to the fourth embodiment. FIG. 14
corresponds to FIG. 4 according to the first embodiment. An example
of the operating method at the stop time since the rated load until
extinguishing will be described with reference to FIG. 14. In FIG.
14, a horizontal axis represents the gas turbine load and the gas
turbine load is lighter as being closer to a right side.
Furthermore, an upper row of FIG. 14 depicts changes in the flow
rates of the startup fuel f1 and the main fuel f2, and a lower row
thereof depicts a change in the flow rate of the gaseous fuel
supplied to the inner fuel nozzles 21 and the outer fuel nozzles 22
and 23 of the pilot burner 31 and the main burners 32 along with
burner schematic diagrams.
[0102] Stop procedures according to the present embodiment are
similar to those according to the first embodiment except that the
procedure (8) in the four procedures (5) to (8) described in the
first embodiment is divided into two stages of procedures (8A) and
(8B). The procedures (8A) and (8B) will be described hereinafter.
Similarly to the first embodiment, upon execution of the procedures
(5) to (7), the following procedures (8A) and (8B) are executed. It
is noted that while the three fuel control valves 65A to 65C are
provided for the startup fuel f1 in the present embodiment, the
fuel control valves 65A to 65C are similarly controlled in the
procedures (5) to (7). Likewise, while the three fuel control
valves 66A to 66C are provided for the main fuel f2, the fuel
control valves 66A to 66C are similarly controlled in the
procedures (5) to (7).
Procedure (8A)
[0103] When the gas turbine load falls down to a sixth set value
L6A (<L5) after execution of the procedure (7), the controller
70 outputs the signals S2, S4, and S5A to S5C (FIG. 11) to the fuel
shut valve 62 and the fuel control valves 64 and 65A to 65C to
execute the procedure (8A). In the procedure (8A), the controller
70 lowers the opening degrees of the fuel control valves 64 and 65A
to 65C at, for example, a specified increasing rate in the state of
releasing the fuel shut valve 62. During this time, the fuel shut
valve 63 and the fuel control valves 65 and 66A to 66C are closed
and the firing state is the state of the single firing of the
startup fuel f1. In the case of operator's regulating the fuel flow
rates, the operator manually operates the opening degrees of the
fuel shut valves 62 and 63 and the fuel control valves 64, 65, 65A
to 65C, and 66A to 66C using the operation device (not depicted) as
described above.
Procedure (8B)
[0104] When the gas turbine load falls down to a set value L6B
(<L6A), the controller 70 outputs the signals S2, S4, SSA, and
S5B (FIG. 11) to the fuel shut valve 62 and the fuel control valves
64, 65A, and 65B to execute the procedure (8B). In the procedure
(8B), the controller 70 lowers the opening degrees of the fuel
control valves 64, 65A, and 65B down to zero at, for example, a
specified increasing rate in the state of releasing the fuel shut
valve 62. In the course, the combustor 3 is extinguished and the
stop operation is over. During this time, the fuel shut valve 63
and the fuel control valves 65, 65C, and 66A to 66C are closed and
the number of injection burners for the startup fuel f1 is reduced
to two, that is, the injection burners for the startup fuel f1 are
the inner burners F11 and F21. In the case of operator's regulating
the fuel flow rates, the operator manually operates the opening
degrees of the fuel shut valves 62 and 63 and the fuel control
valves 64, 65, 65A to 65C, and 66A to 66C using the operation
device (not depicted) as described above.
--Advantages--
[0105] Configuring the multi-burner by applying a burner
configuration according to the first to third embodiments to the
pilot burner 31 and the main burners 32 as appropriate enables the
fourth embodiment to obtain similar advantages to those of the
preceding embodiments or advantages as a combination of the
advantages of these preceding embodiments even if the combustor 3
is used for a large-capacity gas turbine.
* * * * *